/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2024 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include "SDL_internal.h"

#ifdef SDL_VIDEO_DRIVER_X11

#include <X11/cursorfont.h>
#include "SDL_x11video.h"
#include "SDL_x11mouse.h"
#include "SDL_x11xinput2.h"
#include "../SDL_video_c.h"
#include "../../events/SDL_mouse_c.h"

struct SDL_CursorData
{
    Cursor cursor;
};

// FIXME: Find a better place to put this...
static Cursor x11_empty_cursor = None;
static bool x11_cursor_visible = true;

static SDL_Cursor *sys_cursors[SDL_HITTEST_RESIZE_LEFT + 1];

static Display *GetDisplay(void)
{
    return SDL_GetVideoDevice()->internal->display;
}

static Cursor X11_CreateEmptyCursor(void)
{
    if (x11_empty_cursor == None) {
        Display *display = GetDisplay();
        char data[1];
        XColor color;
        Pixmap pixmap;

        SDL_zeroa(data);
        color.red = color.green = color.blue = 0;
        pixmap = X11_XCreateBitmapFromData(display, DefaultRootWindow(display),
                                           data, 1, 1);
        if (pixmap) {
            x11_empty_cursor = X11_XCreatePixmapCursor(display, pixmap, pixmap,
                                                       &color, &color, 0, 0);
            X11_XFreePixmap(display, pixmap);
        }
    }
    return x11_empty_cursor;
}

static void X11_DestroyEmptyCursor(void)
{
    if (x11_empty_cursor != None) {
        X11_XFreeCursor(GetDisplay(), x11_empty_cursor);
        x11_empty_cursor = None;
    }
}

static SDL_Cursor *X11_CreateCursorAndData(Cursor x11_cursor)
{
    SDL_Cursor *cursor = (SDL_Cursor *)SDL_calloc(1, sizeof(*cursor));
    if (cursor) {
        SDL_CursorData *data = (SDL_CursorData *)SDL_calloc(1, sizeof(*data));
        if (!data) {
            SDL_free(cursor);
            return NULL;
        }
        data->cursor = x11_cursor;
        cursor->internal = data;
    }
    return cursor;
}

static SDL_Cursor *X11_CreateDefaultCursor(void)
{
    // None is used to indicate the default cursor
    return X11_CreateCursorAndData(None);
}

#ifdef SDL_VIDEO_DRIVER_X11_XCURSOR
static Cursor X11_CreateXCursorCursor(SDL_Surface *surface, int hot_x, int hot_y)
{
    Display *display = GetDisplay();
    Cursor cursor = None;
    XcursorImage *image;

    image = X11_XcursorImageCreate(surface->w, surface->h);
    if (!image) {
        SDL_OutOfMemory();
        return None;
    }
    image->xhot = hot_x;
    image->yhot = hot_y;
    image->delay = 0;

    SDL_assert(surface->format == SDL_PIXELFORMAT_ARGB8888);
    SDL_assert(surface->pitch == surface->w * 4);
    SDL_memcpy(image->pixels, surface->pixels, (size_t)surface->h * surface->pitch);

    cursor = X11_XcursorImageLoadCursor(display, image);

    X11_XcursorImageDestroy(image);

    return cursor;
}
#endif // SDL_VIDEO_DRIVER_X11_XCURSOR

static Cursor X11_CreatePixmapCursor(SDL_Surface *surface, int hot_x, int hot_y)
{
    Display *display = GetDisplay();
    XColor fg, bg;
    Cursor cursor = None;
    Uint32 *ptr;
    Uint8 *data_bits, *mask_bits;
    Pixmap data_pixmap, mask_pixmap;
    int x, y;
    unsigned int rfg, gfg, bfg, rbg, gbg, bbg, fgBits, bgBits;
    size_t width_bytes = ((surface->w + 7) & ~((size_t)7)) / 8;

    data_bits = SDL_calloc(1, surface->h * width_bytes);
    if (!data_bits) {
        return None;
    }

    mask_bits = SDL_calloc(1, surface->h * width_bytes);
    if (!mask_bits) {
        SDL_free(data_bits);
        return None;
    }

    // Code below assumes ARGB pixel format
    SDL_assert(surface->format == SDL_PIXELFORMAT_ARGB8888);

    rfg = gfg = bfg = rbg = gbg = bbg = fgBits = bgBits = 0;
    for (y = 0; y < surface->h; ++y) {
        ptr = (Uint32 *)((Uint8 *)surface->pixels + y * surface->pitch);
        for (x = 0; x < surface->w; ++x) {
            int alpha = (*ptr >> 24) & 0xff;
            int red = (*ptr >> 16) & 0xff;
            int green = (*ptr >> 8) & 0xff;
            int blue = (*ptr >> 0) & 0xff;
            if (alpha > 25) {
                mask_bits[y * width_bytes + x / 8] |= (0x01 << (x % 8));

                if ((red + green + blue) > 0x40) {
                    fgBits++;
                    rfg += red;
                    gfg += green;
                    bfg += blue;
                    data_bits[y * width_bytes + x / 8] |= (0x01 << (x % 8));
                } else {
                    bgBits++;
                    rbg += red;
                    gbg += green;
                    bbg += blue;
                }
            }
            ++ptr;
        }
    }

    if (fgBits) {
        fg.red = rfg * 257 / fgBits;
        fg.green = gfg * 257 / fgBits;
        fg.blue = bfg * 257 / fgBits;
    } else {
        fg.red = fg.green = fg.blue = 0;
    }

    if (bgBits) {
        bg.red = rbg * 257 / bgBits;
        bg.green = gbg * 257 / bgBits;
        bg.blue = bbg * 257 / bgBits;
    } else {
        bg.red = bg.green = bg.blue = 0;
    }

    data_pixmap = X11_XCreateBitmapFromData(display, DefaultRootWindow(display),
                                            (char *)data_bits,
                                            surface->w, surface->h);
    mask_pixmap = X11_XCreateBitmapFromData(display, DefaultRootWindow(display),
                                            (char *)mask_bits,
                                            surface->w, surface->h);
    cursor = X11_XCreatePixmapCursor(display, data_pixmap, mask_pixmap,
                                     &fg, &bg, hot_x, hot_y);
    X11_XFreePixmap(display, data_pixmap);
    X11_XFreePixmap(display, mask_pixmap);
    SDL_free(data_bits);
    SDL_free(mask_bits);

    return cursor;
}

static SDL_Cursor *X11_CreateCursor(SDL_Surface *surface, int hot_x, int hot_y)
{
    Cursor x11_cursor = None;

#ifdef SDL_VIDEO_DRIVER_X11_XCURSOR
    if (SDL_X11_HAVE_XCURSOR) {
        x11_cursor = X11_CreateXCursorCursor(surface, hot_x, hot_y);
    }
#endif
    if (x11_cursor == None) {
        x11_cursor = X11_CreatePixmapCursor(surface, hot_x, hot_y);
    }
    return X11_CreateCursorAndData(x11_cursor);
}

static unsigned int GetLegacySystemCursorShape(SDL_SystemCursor id)
{
    switch (id) {
        // X Font Cursors reference:
        // http://tronche.com/gui/x/xlib/appendix/b/
        case SDL_SYSTEM_CURSOR_DEFAULT: return XC_left_ptr;
        case SDL_SYSTEM_CURSOR_TEXT: return XC_xterm;
        case SDL_SYSTEM_CURSOR_WAIT: return XC_watch;
        case SDL_SYSTEM_CURSOR_CROSSHAIR: return XC_tcross;
        case SDL_SYSTEM_CURSOR_PROGRESS: return XC_watch;
        case SDL_SYSTEM_CURSOR_NWSE_RESIZE: return XC_top_left_corner;
        case SDL_SYSTEM_CURSOR_NESW_RESIZE: return XC_top_right_corner;
        case SDL_SYSTEM_CURSOR_EW_RESIZE: return XC_sb_h_double_arrow;
        case SDL_SYSTEM_CURSOR_NS_RESIZE: return XC_sb_v_double_arrow;
        case SDL_SYSTEM_CURSOR_MOVE: return XC_fleur;
        case SDL_SYSTEM_CURSOR_NOT_ALLOWED: return XC_pirate;
        case SDL_SYSTEM_CURSOR_POINTER: return XC_hand2;
        case SDL_SYSTEM_CURSOR_NW_RESIZE: return XC_top_left_corner;
        case SDL_SYSTEM_CURSOR_N_RESIZE: return XC_top_side;
        case SDL_SYSTEM_CURSOR_NE_RESIZE: return XC_top_right_corner;
        case SDL_SYSTEM_CURSOR_E_RESIZE: return XC_right_side;
        case SDL_SYSTEM_CURSOR_SE_RESIZE: return XC_bottom_right_corner;
        case SDL_SYSTEM_CURSOR_S_RESIZE: return XC_bottom_side;
        case SDL_SYSTEM_CURSOR_SW_RESIZE: return XC_bottom_left_corner;
        case SDL_SYSTEM_CURSOR_W_RESIZE: return XC_left_side;
        case SDL_SYSTEM_CURSOR_COUNT: break;  // so the compiler might notice if an enum value is missing here.
    }

    SDL_assert(0);
    return 0;
}

static SDL_Cursor *X11_CreateSystemCursor(SDL_SystemCursor id)
{
    SDL_Cursor *cursor = NULL;
    Display *dpy = GetDisplay();
    Cursor x11_cursor = None;

#ifdef SDL_VIDEO_DRIVER_X11_XCURSOR
    if (SDL_X11_HAVE_XCURSOR) {
        x11_cursor = X11_XcursorLibraryLoadCursor(dpy, SDL_GetCSSCursorName(id, NULL));
    }
#endif

    if (x11_cursor == None) {
        x11_cursor = X11_XCreateFontCursor(dpy, GetLegacySystemCursorShape(id));
    }

    if (x11_cursor != None) {
        cursor = X11_CreateCursorAndData(x11_cursor);
    }

    return cursor;
}

static void X11_FreeCursor(SDL_Cursor *cursor)
{
    Cursor x11_cursor = cursor->internal->cursor;

    if (x11_cursor != None) {
        X11_XFreeCursor(GetDisplay(), x11_cursor);
    }
    SDL_free(cursor->internal);
    SDL_free(cursor);
}

static bool X11_ShowCursor(SDL_Cursor *cursor)
{
    Cursor x11_cursor = 0;

    if (cursor) {
        x11_cursor = cursor->internal->cursor;
    } else {
        x11_cursor = X11_CreateEmptyCursor();
    }

    // FIXME: Is there a better way than this?
    {
        SDL_VideoDevice *video = SDL_GetVideoDevice();
        Display *display = GetDisplay();
        SDL_Window *window;

        x11_cursor_visible = !!cursor;

        for (window = video->windows; window; window = window->next) {
            SDL_WindowData *data = window->internal;
            if (data) {
                if (x11_cursor != None) {
                    X11_XDefineCursor(display, data->xwindow, x11_cursor);
                } else {
                    X11_XUndefineCursor(display, data->xwindow);
                }
            }
        }
        X11_XFlush(display);
    }
    return true;
}

static void X11_WarpMouseInternal(Window xwindow, float x, float y)
{
    SDL_VideoData *videodata = SDL_GetVideoDevice()->internal;
    Display *display = videodata->display;
    bool warp_hack = false;

    // XWayland will only warp the cursor if it is hidden, so this workaround is required.
    if (videodata->is_xwayland && x11_cursor_visible) {
        warp_hack = true;
    }

    if (warp_hack) {
        X11_ShowCursor(NULL);
    }
#ifdef SDL_VIDEO_DRIVER_X11_XINPUT2
    int deviceid = 0;
    if (X11_Xinput2IsInitialized()) {
        /* It seems XIWarpPointer() doesn't work correctly on multi-head setups:
         * https://developer.blender.org/rB165caafb99c6846e53d11c4e966990aaffc06cea
         */
        if (ScreenCount(display) == 1) {
            X11_XIGetClientPointer(display, None, &deviceid);
        }
    }
    if (deviceid != 0) {
        SDL_assert(SDL_X11_HAVE_XINPUT2);
        X11_XIWarpPointer(display, deviceid, None, xwindow, 0.0, 0.0, 0, 0, x, y);
    } else
#endif
    {
        X11_XWarpPointer(display, None, xwindow, 0, 0, 0, 0, (int)x, (int)y);
    }

    if (warp_hack) {
        X11_ShowCursor(SDL_GetCursor());
    }
    X11_XSync(display, False);
    videodata->global_mouse_changed = true;
}

static bool X11_WarpMouse(SDL_Window *window, float x, float y)
{
    SDL_WindowData *data = window->internal;

#ifdef SDL_VIDEO_DRIVER_X11_XFIXES
    // If we have no barrier, we need to warp
    if (data->pointer_barrier_active == false) {
        X11_WarpMouseInternal(data->xwindow, x, y);
    }
#else
    X11_WarpMouseInternal(data->xwindow, x, y);
#endif
    return true;
}

static bool X11_WarpMouseGlobal(float x, float y)
{
    X11_WarpMouseInternal(DefaultRootWindow(GetDisplay()), x, y);
    return true;
}

static bool X11_SetRelativeMouseMode(bool enabled)
{
    if (!X11_Xinput2IsInitialized()) {
        return SDL_Unsupported();
    }
    return true;
}

static bool X11_CaptureMouse(SDL_Window *window)
{
    Display *display = GetDisplay();
    SDL_Window *mouse_focus = SDL_GetMouseFocus();

    if (window) {
        SDL_WindowData *data = window->internal;

        /* If XInput2 is handling the pointer input, non-confinement grabs will always fail with 'AlreadyGrabbed',
         * since the pointer is being grabbed by XInput2.
         */
        if (!data->xinput2_mouse_enabled || data->mouse_grabbed) {
            const unsigned int mask = ButtonPressMask | ButtonReleaseMask | PointerMotionMask | FocusChangeMask;
            Window confined = (data->mouse_grabbed ? data->xwindow : None);
            const int rc = X11_XGrabPointer(display, data->xwindow, False,
                                            mask, GrabModeAsync, GrabModeAsync,
                                            confined, None, CurrentTime);
            if (rc != GrabSuccess) {
                return SDL_SetError("X server refused mouse capture");
            }
        }
    } else if (mouse_focus) {
        SDL_UpdateWindowGrab(mouse_focus);
    } else {
        X11_XUngrabPointer(display, CurrentTime);
    }

    X11_XSync(display, False);

    return true;
}

static SDL_MouseButtonFlags X11_GetGlobalMouseState(float *x, float *y)
{
    SDL_VideoData *videodata = SDL_GetVideoDevice()->internal;
    SDL_DisplayID *displays;
    Display *display = GetDisplay();
    int i;

    // !!! FIXME: should we XSync() here first?

    if (!X11_Xinput2IsInitialized()) {
        videodata->global_mouse_changed = true;
    }

    // check if we have this cached since XInput last saw the mouse move.
    // !!! FIXME: can we just calculate this from XInput's events?
    if (videodata->global_mouse_changed) {
        displays = SDL_GetDisplays(NULL);
        if (displays) {
            for (i = 0; displays[i]; ++i) {
                SDL_DisplayData *data = SDL_GetDisplayDriverData(displays[i]);
                if (data) {
                    Window root, child;
                    int rootx, rooty, winx, winy;
                    unsigned int mask;
                    if (X11_XQueryPointer(display, RootWindow(display, data->screen), &root, &child, &rootx, &rooty, &winx, &winy, &mask)) {
                        XWindowAttributes root_attrs;
                        SDL_MouseButtonFlags buttons = 0;
                        buttons |= (mask & Button1Mask) ? SDL_BUTTON_LMASK : 0;
                        buttons |= (mask & Button2Mask) ? SDL_BUTTON_MMASK : 0;
                        buttons |= (mask & Button3Mask) ? SDL_BUTTON_RMASK : 0;
                        // Use the SDL state for the extended buttons - it's better than nothing
                        buttons |= (SDL_GetMouseState(NULL, NULL) & (SDL_BUTTON_X1MASK | SDL_BUTTON_X2MASK));
                        /* SDL_DisplayData->x,y point to screen origin, and adding them to mouse coordinates relative to root window doesn't do the right thing
                         * (observed on dual monitor setup with primary display being the rightmost one - mouse was offset to the right).
                         *
                         * Adding root position to root-relative coordinates seems to be a better way to get absolute position. */
                        X11_XGetWindowAttributes(display, root, &root_attrs);
                        videodata->global_mouse_position.x = root_attrs.x + rootx;
                        videodata->global_mouse_position.y = root_attrs.y + rooty;
                        videodata->global_mouse_buttons = buttons;
                        videodata->global_mouse_changed = false;
                        break;
                    }
                }
            }
            SDL_free(displays);
        }
    }

    SDL_assert(!videodata->global_mouse_changed); // The pointer wasn't on any X11 screen?!

    *x = (float)videodata->global_mouse_position.x;
    *y = (float)videodata->global_mouse_position.y;
    return videodata->global_mouse_buttons;
}

void X11_InitMouse(SDL_VideoDevice *_this)
{
    SDL_Mouse *mouse = SDL_GetMouse();

    mouse->CreateCursor = X11_CreateCursor;
    mouse->CreateSystemCursor = X11_CreateSystemCursor;
    mouse->ShowCursor = X11_ShowCursor;
    mouse->FreeCursor = X11_FreeCursor;
    mouse->WarpMouse = X11_WarpMouse;
    mouse->WarpMouseGlobal = X11_WarpMouseGlobal;
    mouse->SetRelativeMouseMode = X11_SetRelativeMouseMode;
    mouse->CaptureMouse = X11_CaptureMouse;
    mouse->GetGlobalMouseState = X11_GetGlobalMouseState;

    SDL_HitTestResult r = SDL_HITTEST_NORMAL;
    while (r <= SDL_HITTEST_RESIZE_LEFT) {
        switch (r) {
        case SDL_HITTEST_NORMAL: sys_cursors[r] = X11_CreateSystemCursor(SDL_SYSTEM_CURSOR_DEFAULT); break;
        case SDL_HITTEST_DRAGGABLE: sys_cursors[r] = X11_CreateSystemCursor(SDL_SYSTEM_CURSOR_DEFAULT); break;
        case SDL_HITTEST_RESIZE_TOPLEFT: sys_cursors[r] = X11_CreateSystemCursor(SDL_SYSTEM_CURSOR_NW_RESIZE); break;
        case SDL_HITTEST_RESIZE_TOP: sys_cursors[r] = X11_CreateSystemCursor(SDL_SYSTEM_CURSOR_N_RESIZE); break;
        case SDL_HITTEST_RESIZE_TOPRIGHT: sys_cursors[r] = X11_CreateSystemCursor(SDL_SYSTEM_CURSOR_NE_RESIZE); break;
        case SDL_HITTEST_RESIZE_RIGHT: sys_cursors[r] = X11_CreateSystemCursor(SDL_SYSTEM_CURSOR_E_RESIZE); break;
        case SDL_HITTEST_RESIZE_BOTTOMRIGHT: sys_cursors[r] = X11_CreateSystemCursor(SDL_SYSTEM_CURSOR_SE_RESIZE); break;
        case SDL_HITTEST_RESIZE_BOTTOM: sys_cursors[r] = X11_CreateSystemCursor(SDL_SYSTEM_CURSOR_S_RESIZE); break;
        case SDL_HITTEST_RESIZE_BOTTOMLEFT: sys_cursors[r] = X11_CreateSystemCursor(SDL_SYSTEM_CURSOR_SW_RESIZE); break;
        case SDL_HITTEST_RESIZE_LEFT: sys_cursors[r] = X11_CreateSystemCursor(SDL_SYSTEM_CURSOR_W_RESIZE); break;
        }
        r++;
    }

    SDL_SetDefaultCursor(X11_CreateDefaultCursor());
}

void X11_QuitMouse(SDL_VideoDevice *_this)
{
    SDL_VideoData *data = _this->internal;
    SDL_XInput2DeviceInfo *i;
    SDL_XInput2DeviceInfo *next;
    int j;

    for (j = 0; j < SDL_arraysize(sys_cursors); j++) {
        X11_FreeCursor(sys_cursors[j]);
        sys_cursors[j] = NULL;
    }

    for (i = data->mouse_device_info; i; i = next) {
        next = i->next;
        SDL_free(i);
    }
    data->mouse_device_info = NULL;

    X11_DestroyEmptyCursor();
}

void X11_SetHitTestCursor(SDL_HitTestResult rc)
{
    if (rc == SDL_HITTEST_NORMAL || rc == SDL_HITTEST_DRAGGABLE) {
        SDL_SetCursor(NULL);
    } else {
        X11_ShowCursor(sys_cursors[rc]);
    }
}

#endif // SDL_VIDEO_DRIVER_X11
